The outside part of discs is rich with nerve supply. Often, with
pain, surrounding ligaments and bones danger sensors will be activated too.
A disc injury will likely result in stiffness and pain the next day after irritation.
Degeneration is a normal part of aging for the discs. At least ⅓ people with no low back pain show marked bulges on MRI. Remember that the disc is almost glued to the vertebrae, and therefore will age together.
Discs never slip, or get out of place. They can be irritated, bulged, herniated. They can squeeze a nerve physically. But this not always causes pain.
Discs heal slowly over time. Age changes can often not be differentiated from injury changes.
Discs are not delicate structures. They are integrated and supported by powerful surrounding tissues.